Micro-Scale Simulation of Evaporation, Condensation and Transport in Porous Media
Abstract
Sub-pore scale modeling of flow in porous media is gaining momentum. The concept of Digital Core Analysis deals with measurements of virtual core and the purpose of such modeling is to replace conventional and special core analysis when the latter are not feasible. One of the challenging concepts in micro-scale simulation of porous media is consideration of phase change phenomena. Mass and heat transfer equations have to be considered simultaneously to capture complexities involved in the evaporation and condensation processes. Therefore, a numerical scheme based on the Volume-of-Fluid method was implemented using the OpenFOAM open-source CFD package along with four phase change models.
The aforementioned approach is extended in the modeling of phase change within a porous medium. Surface roughness is introduced by the incorporation of wedges of variable density and amplitude on the grain surface. A further introduced complication is that the individual grains are of different mineralogy and thus of different wettability. It is observed that steam condenses first in the smallest of wedges, which act as nucleation sites. A condensate film was generated around high roughness density areas and the amount of condensate being generated in the roughened medium was significantly larger than the generated condensate in smooth surface. Water spreads on water-wet surfaces. Snap-off is observed in several cases leading to temporary trapping of vapor. Grid size effects are also addressed.
The application of this modeling effort is the condensation of steam in thermal recovery methods. The effect of temperature on bitumen viscosity reduction during steam flooding operation as well as steam condensation, trapping of the oil behind the steam front and finally countercurrent flow of steam and condensate-bitumen due to gravity effects.
Description
Keywords
Engineering--Petroleum
Citation
Etemad, S. (2016). Micro-Scale Simulation of Evaporation, Condensation and Transport in Porous Media (Master's thesis, University of Calgary, Calgary, Canada). Retrieved from https://prism.ucalgary.ca. doi:10.11575/PRISM/26908